In offshore drilling operations from a floating drilling vessel, it is necessary to initiate drilling by placing a temporary guide base structure on the ocean floor. The temporary guide base permits proper positioning of a drill string for initial drilling operations. Thereafter, a permanent guide base structure is added to the temporary guide base structure and is built up therefrom. Prior to commencing drilling operations, it has been required heretofore to place the temporary guide base on the ocean floor by attaching it to a drill string and a running tool and lowering the temporary guide base with the drill string and running tool by continually attaching additional sections of drill pipe to the drill string until the entire apparatus reaches the ocean floor. In that operation the function of the running tool is to facilitate the connection of the temporary guide base and drill string and to insure proper positioning of the guide base on the drilling site. Thereafter the drill string and running tool are released from the temporary guide base and returned to the drilling vessel by continually removing drill pipe sections until the entire drill string has been removed and the running tool is returned to the surface. Retrieving the entire drill string is required to remove the running tool from the bottom of the drill string as it is impossible to drill with the running tool in place. Once the running tool is removed and the drill bit is attached to the drill string, the drill string is returned, along guide lines, to the temporary guide base by continually adding sections of drill pipe until the drill string is properly placed within the temporary guide base on the ocean floor. Only at this point can drilling operations be commenced.
In summary, to begin drilling operations three main steps were required. Basically, these steps were lowering the temporary guide base, running tool, and drill string, section by section, to the drilling site; returning the drill string and running tool to the vessel, section be section; removing the running tool and placing the drill bit on the drill string; and returning the drill string to the ocean floor section by section. This complete process requires a great deal of time and is therefore very expensive.